Add 1M peptide datasets and generation scripts

- Added 8 peptide datasets (1M peptides each):
  * Random method: 8-mer, 9-mer, 10-mer, 11-mer
  * Reference proteome method: 8-mer, 9-mer, 10-mer, 11-mer
- Added generate_1M_peptide_datasets.py script
- Updated .gitignore to exclude large protein.faa file
- Total: 8M peptides for algorithm benchmarking

Author: Chris2004m

.gitignore

@@ -14,4 +14,26 @@ process-todos.md
 # Generated pVACbind outputs
 results/pvacbind*/
 
+# Large reference proteome file (too big for GitHub)
+data/protein.faa
+
+# Python cache files
+__pycache__/
+*.pyc
+*.pyo
+*.pyd
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+